I'm trying to dial in the settings for a new spool of eSun red PETG. I've run some single wall calibration cubes, and I'm getting tiny pin holes in the walls. This is in the middle of walls well away from the starting point, so it doesn't have anything to do with retraction, coasting, wiping, etc.

I'm doing 0.2 mm layers, and the auto-width setting of 0.42 mm. There's a bit of variation in the wall thickness, but on average, I'm getting pretty close at an extrusion multiplier of 1.0. I've tried 255C and 260C so far for temperatures, with an 85C bed, and no cooling. I've got my general speeds cranked down to match some of the PETG settings folks here have recommended, and the perimeter speed is set much lower than that.

I don't know if I've got a bad spool of filament, drive issues, or something else is going on.

It's an M2E, with a 0.35 mm nozzle. I've used Hatchbox white & black PETG successfully in the past, using Jules's detailed notes on PETG printer settings. This stuff behaves a bit different from the Hatchbox filaments.

I'm re-running the 240C temperature test. First attempt lost bed adhesion, so I may have to crank up the temperature on the first layer to get it to stick.

well you should have NO adhesion issues if using the polymide tape that is stock on the M2 glass. If just glass, then Elmer's purple glue stick worked but I prefer the tape. If it is not sticking and you are using polymide, then your starting height is too high.

Here is a link to a factory file for my calibration square which uses a Extrusion multiplier of .4 not 4.2. This one is a final and should be right if your filament is the same diameter as mine but may need to be tweaked up or down .1 This was set up for a different model and I just plugged in the calibrations square and set thin wall to allow. This is S3D 4.01 not the bug infested just release never beta tested 4.1 Stay away form that thing.. http://misc.airscapesart.com/petg/singl ... mm.factory

Run this and if it prints without falling off, it should be 2mm tall if you starting height is correct. I normally will adjust starting height so the wall is 1.99 mm. It should be .4mm wall thickness, I will normally let it slide if it is .41 or even .42 knowing I am just slightly over extruded.
My retraction may be a bit too much and too fast but I don't worry about the Z axis line in the part too much.

If you do not know how to adjust your starting height with the firmware M206 offset in the terminal screen, let me know and I will try and write it up. Not hard once you know how, I can normally change a hot end and have the height correct with 2 prints of a square, if I already know my Extrusion multiplier is correct. Once I find out the EM for a roll of filament I right the EM, EW , Nozzle size and temps on the side of the roll.

Thanks for the factory file! I'm a bit confused by this "Here is a link to a factory file for my calibration square which uses a Extrusion multiplier of .4 not 4.2." Do you mean width, and if so, I assume you meant ".4 not .42"?

For adhesion, I've tried polyimide, glass, glass with glue stick and glass with hairspray. The last one is my favorite. Prints stick well, but once it's cooled down, they pop right off without any force. Some people recommend re-applying it every few prints, but I've been using one application for weeks.

I started having adhesion issues a few days ago, and removed, cleaned & re-sprayed my build plate. I think it may be tilted slightly now, because I only seem to have adhesion issues in one corner. I've been printing sequential test models, and the one in the front left corner is letting go. I'll try the full re-level routine tomorrow.

The test cube I did at 245C looks better than the higher temp ones, with fewer pin holes, but it's losing some layer adhesion. I've got a rush job that isn't too critical, and I'm running with 245C for now. The model has got enough contact area with the build plate that it should stay put OK, and I'm printing in the middle of the plate, which has been fine. Once I get that job done, I'll check out your factory file and run some more test prints.

yes, .4 not the .42 you had said you were using. My M2 has a bowed gantry, with the sides out as much as .06 higher than the center, so I do most of my printing in the center if it small and since I only print stuff for myself, don't have to fill the bed. One of these winter days here soon I will get me some shims and fix it..